A self-contained underwater breathing apparatus typically has a gas storage vessel with a first-stage regulator mounted thereon. The function of this regulator is to reduce the tank pressure to some lower value. A hose communicates the first-stage regulator fluid outlet with the inlet of a second-stage regulator, typically located at or near the diver's mouth. This is usually a demand-type regulator that compensates for the diver's depth, and that admits air on a demanded basis. Examples of first-stage regulators are representatively shown and described in U.S. Pat. Nos. 3,211,175 and 3,522,818, the aggregate disclosures of which are hereby incorporated reference.
One problem with such prior art or conventional first-stage regulators is that the pressure of fluid delivered at the end of the hose to the second-stage inlet tends to fall off sharply at increased flows through the regulator. To this end, personnel employed by the assignee of the present invention have attempted to devise a device that would better maintain the pressure at the distal end of the hose at increased flows through the regulator. One such implementation is shown in abandoned U.S. patent application Ser. No. 07/124,922, filed Nov. 24, 1987, and entitled "Pressure Regulator". An Assignment of this invention and application in favor of Harsco Corporation was recorded in the Patent and Trademark Office on Nov. 24, 1988 at Reel 4814, Frames 442-443. The subject matter disclosed and claimed in this application was invented by James E. J. Fox, who was then, and is now, an employee of Harsco Corporation, and is a co-inventor of the subject matter disclosed and claimed in this application. It is believed that the regulator shown in this application was sold more than one year prior to the filing of this application, and therefore qualifies as prior art under 35 U.S.C. .sctn.102(b). As shown in that abandoned application, a downstream sensing passageway was provided between the outlet conduit and the valve actuation chamber. However, the size and placement of that sensing passageway did not allow the body of the regulator to be optimally reduced to a practical minimum. Nor did it increase the dynamic responsiveness of the regulator to the extent now provided by the present Applicants' further improvement.
In any event, the problem has continued, and has received the present Applicants' consideration. The present Applicants have devised a further improved arrangement that appears to further increase the dynamic responsiveness of the regulator to changes in the demanded flows, and to better maintain the outlet pressure at the distal end of the hose at increased flows through the regulator.
It would be generally desirable to provide an improved pressure regulator that has the capability of restraining the delivered outlet pressure at the end of the hose from falling off sharply and substantially at increased demanded flows through the first-stage regulator.